>>7287013So you could think of it as being the pale glass sponge girl, halfway encased in the rigid, crystalline lattice of your spicules and consequently unable to move around well (smaller sponges are generally more flexible and fragile, but their skeleton later fuses together into a reinforced structure.) Eventually, a little syllid girl would settle in the numerous channels that compose your sponge half, and you'd get to act her parent or elder sister, teaching her the ways of sessile life (hexactenellids are the least mobile sponges, and that's saying quite a bit.) and ensuring that she develops as a well-educated, proper young lady. Of course, as you'd be the sole influence over her, she'd see you as a role model and later bud into an elegant little lesbian, her sisterly affection for you eventually changing into romantic feelings. Since no /jp/ user would refuse her "adopted" little sister, you'd then become a couple, with her taking a more active role in your relationship due to your obvious problems with mobility. As you'd be her admired elder sister, she'd constantly strive to act as a girlfriend befitting you, earnestly doing her best and using both her young woman and branched polychaete halves to better serve as your lover.
Since your protective armor would constrain your growth you'd still be a flat-chested little girl despite being much older than her, but by this time she'd have developed into a cute young maiden, rubbing her full breasts against your washboard chest and pushing her slender fingers in your maidenhood every night while her chaetae brush against the inner walls of your sponge half and the branches of her annelid side slide across your body, uniting herself with you in a manner human couples cannot hope to. And after she climaxes while repeatedly calling your name and confessing her love to you, she'd fall asleep in your arms, and you'd get to gently pat her head until you too fall asleep.
